Luffing-crane.



F. SMULDERS.

LUFFING CRANE.

APPLICATION FILED DBO. 10, 1912.

1,096,400. Patented May 12, 1914,

FRANS SMULDERS, 0F ROTTERDAM, NETHERLANDS.

LUFFING-CRANE.

Specification of Letters Patent.

Application fi1ed December 10, 1912.

Patented May 12, 1914.

Serial No. 735,905.

To all whom it may concern Be it known that I, FnANs SMULnnRs, subject of the Queen of the Netherlands, residing at Eendrachtsweg 9, Rotterdam, Netherlands, have invented certain new and useful Improvements in Lufling-Cranes, of which the following is a specification.

It is generally necessary with cranes and especially in sluing floating cranes, that the crane load should itself be deposited on the pontoon or equivalent member which supports the crane. To this end it is necessary in most cases, to luff, or what is the same thing, alter the radius of the crane, together with its load, which adjustment is ordinarily effected by means of a counterweight or lutting screw or equivalent device arranged at the end of the jib opposite to that where the load is applied. The lufling screw should have a length proportional to the length of the jib. The consequence is that the screw frequently has a very great length, so that it is necessary to provide for its mounting and guidance a framework of considerable height above the deck of the pentoon. In such cases it is necessary, in consequence, for reasons of stability, to increase the size of the pontoon. Moreover, in known arrangements, the load on the jib pivot, comprises, on the one hand, the weight of the raised load augmented by part of the weight of the jib itself and the counter weight, and on the other hand, the force necessary for luffing the jib and its lead, which force is often very great.

The present invention has for its object mechanism for adjusting the jibs of sluing cranes, which is particularly applicable to floating cranes, allows of the height of the frame supporting the lufling screw being reduced to about half what it is ordinarily, and obviates any action, on the jib pivot, of the force for lutfing the jib and its load.

The accompanying drawing shows diagrammatically, by way of example, one form of construction according to this invention.

In the drawings, 1 denotes the crane jib,

pivoting at 2 on a frame suitably mounted necessary for lulling the jib and its load does not act on the pivot 2, for it comprises two equal forces acting in opposite directions on either side of the pivot. The total force expended is the same as that in known systems, which have a lufling screw on one side only of the pivot, while the length of the screw is reduced to about half.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. In a lufiing crane, a crane support, a jib pivoted on a horizontal axis on said support, and two lu'lfing screws for said jib, arranged one on either side of the crane, in a plane containing the longitudinal axis of the crane, said screws acting in opposite dircctions.

2. In a luffing crane, a crane support, a jib pivoted on a horizontal axis on said support, and two lutling screws for said jib, said screws being of equal length and arranged one on either side of the crane, in a plane containing the longitudinal axis of the crane, said screws acting in opposite directions.

In testimony whereof I affix my signature in presence of two witnesses.

FRANS SMULDERS.

Witnesses C. Y. PEOK, J. H. WnLoKrm.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Tatents, Washington, D. C. 

